<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
<style>
</style>
</head>
<body>

<div>fps: <span id="fps"></span></div>



</body>
<script>

const fpsElem = document.querySelector("#fps");

let then = 0;
function render(now) {
  now *= 0.001;                          // convert to seconds
  const deltaTime = now - then;          // compute time since last frame
  then = now;                            // remember time for next frame
  const fps = 1 / deltaTime;             // compute frames per second
  fpsElem.textContent = fps.toFixed(1);  // update fps display
  
  requestAnimationFrame(render);
}
requestAnimationFrame(render);



</script>
